This invention relates generally to methods and systems for recognizing patterns, and, more particularly, to methods and systems for automatic detection of repeating patterns of features.
Repeating stripe features (also referred as “chevron marks”) are used in a variety of applications. In one application, edge marks such as alternating red and blue diagonal stripes located at equal intervals around the edge of the envelope are used, in some countries, to indicate that postal material is airmail. Other marks, such as airmail marks, may overlap the striped edge airmail marks. Stamps may also partially overlap the edge marks. This overlapping of airmail marks and edge marks and of stamps and edge marks at times makes the airmail mark and the stamp difficult to distinguish from the edge marks and, therefore, difficult to detect. Separate detection of the edge marks (“chevron” marks) will reduce any difficulty caused by overlapping of other marks and the edge marks.
While the detection of repeating stripe (“chevron”) marks is not a difficult task for a human observer, the automatic detection of repeating stripe (“chevron”) features (marks) presents unique challenges.
It is therefore an object of this invention to provide methods and systems for automatic detection of repeating patterns of slanted stripe features.
It is a further object of this invention to provide methods and systems for automatic detection of repeating patterns of slanted stripe features (marks) on mail items.